The thread for space cadets!

[Winner]

I haven't been devoting any time to this thread, despite it being something I'm very interested in. So please forgive me it this post is abrupt - but I thought you all might appreciate this. From reddit:

Spoiler :

Thanks for this, I've been looking for a clear chart like this for some time.

That asteroid surprise is completely frightening to me.

(...)

I was later able to determine that I had caught a little bit of a radio play - I started to fall for my own little War Of The Worlds

Cool story.

Well the good news is that the only rocks to slip past our 'sensors' (to use Star Trek terminology) are the very small ones. I don't think we'd miss something bigger than 1 kilometre unless we were extraordinarily inattentive and/or unlucky.

Depending on the size of the asteroid and the time to impact, I'd either attempt to flee the target area, or hide underground. Probably hide underground, because I wouldn't want to miss it (of course assuming it is a small rock that will explode in the atmosphere).

But we should really develop nuke-tipped missiles to blast these little buggers as they're entering the upper atmosphere. It shouldn't be that different from shooting down incoming nuclear warheads, so the military should happily jump at the chance.

 

[hobbsyoyo]

Exactly - that's very different than simply 'blowing it up'. The matter doesn't go away - instead of a single slug travelling in a path it becomes a shotgun blast.

Yup.

Though it has always puzzled me why, when looking to 'blow it up', they don't have many more nukes there to pulverize the pieces even more until it is all small enough to be harmless.

I just suspect we don't know enough about asteroidal geology to safely break one up in a way that would be good and not bad.

 

[Winner]

5 planets "found" around Tau Ceti

And another article on space.com

-> the one in the habitable zone is 4.3 Earth mass, so likely a super-Earth or a small Neptune-like gas giants. Considering Tau Ceti is metal-poor star, it may even be reasonably livable there, if it exists.

 

[LegionSteve]

I find it amazing that they can tell not only that something is orbiting the star, but how many planets and roughly how big and how far away. Awesome

 

[Winner]

We need better telescopes to confirm it, but I have a hunch this is going to be in the right ballpark.

 

[Pokurcz]

For a moment there I thought this was a thread about the filmatization of Enders Game...

 

[Winner]

Wouldn't it be nice if it wasn't one planet with 4.3 Earth-mass, but two planets orbiting a common centre of gravity? Both of them habitable, of course

For a moment there I thought this was a thread about the filmatization of Enders Game...

I don't get the reference.

 

[AdamCrock]

I would love it so much to be a Mars colonist ! Always dreamed to be among the stars but I fear my body would not pass a physical exam + I have many habits and psychological problems + (and the worst) I smoke cigarettes which strictly forbidden on board of any know space vessel and station so.... I'm grounded for the time being

EDIT: It has always baffled me : how do You take a piss in all that spacesuit ?

 

[El_Machinae]

12 ly is actually within a reasonable distance, too. That's within the distance that ejecta from Earth could have traveled. IF Earth-sourced ejecta contained microbes, and IF that ejecta went the right direction, then maybe the Tau Ceti planet has been seeded. A billion years is a fairly long time, even when talking interstellar distances.

More or less likely than a second genesis? I have no idea. Both seem to be incredibly long odds.

 

[Pokurcz]

I don't get the reference.

Its like one of the best SF book of the 80:s, that finally will become a movie next year, a must read.

 

[Winner]

12 ly is actually within a reasonable distance, too. That's within the distance that ejecta from Earth could have traveled. IF Earth-sourced ejecta contained microbes, and IF that ejecta went the right direction, then maybe the Tau Ceti planet has been seeded. A billion years is a fairly long time, even when talking interstellar distances.

More or less likely than a second genesis? I have no idea. Both seem to be incredibly long odds.

This thought has a little problem - you're assuming constant distance between Sol and Tau Ceti.

---

BTW, is anybody else intrigued by the fact we're seeing all these systems with super-Earths in very tightly-packed orbits? It is starting to look like our Solar System may be an aberration rather than a rule. Earth certainly looks rather small compared to the terrestrial planets we've found so far, though this may be due to our observation bias.

But if that was true, the better - for any intelligent species on such planets getting to space would be even harder than it is for us. Less competition

 

[Crezth]

EDIT: It has always baffled me : how do You take a piss in all that spacesuit ?

Diapers.

 

[Winner]

Diapers.

Don't they have this condom-like thing which captures the urine? Or was that only in Apollo-era suits?

 

[warpus]

BTW, is anybody else intrigued by the fact we're seeing all these systems with super-Earths in very tightly-packed orbits? It is starting to look like our Solar System may be an aberration rather than a rule. Earth certainly looks rather small compared to the terrestrial planets we've found so far, though this may be due to our observation bias.

I was under the impression that we were finding such large planets and nothing smaller because the first extrasolar planet finding technology we came up with was only good enough to find those giants.. As the technology got better, we started finding smaller and smaller planets, but I don't think we have the technology yet to find something the size of earth? Do we?

 

[Winner]

I was under the impression that we were finding such large planets and nothing smaller because the first extrasolar planet finding technology we came up with was only good enough to find those giants.. As the technology got better, we started finding smaller and smaller planets, but I don't think we have the technology yet to find something the size of earth? Do we?

The transition method should see things smaller than Earth. Yet we see awful lot of stars with super-terrestrial planets (not just huge gas giants, I am talking about the category of rocky planets here).

Of course now it's still just an assumption and I myself have warned here about making such assumptions based on incomplete data, but still - Tau Ceti is a metal-poor star, it *should* have had light, small, or none rocky planets. Instead it seems to have plenty of them with a pretty significant mass. This begs the question why are terrestrial planets in our metal-rich solar system so tiny?

 

[warpus]

But would it see things smaller than Earth as close to the sun as we are? I didn't think we had the technology to detect planet that size, unless they were further away from the star.

 

[Michkov]

The farther out a planet is the more likelier it is that it wont cross in front of its star. Also it takes longer to come back around, as it takes 3? detected passes for a candidate, it could just be a matter of us not watching long enough.

If you give it some time I think the picture will even itself out.

 

[Winner]

But would it see things smaller than Earth as close to the sun as we are? I didn't think we had the technology to detect planet that size, unless they were further away from the star.

The transition method (you're looking for drops in the stars overall brightness) should see things even smaller than Earth. The closer to the star, the better the chance this method will uncover them.

Some of the planets found by the Kepler *are* smaller than Earth. Most of them (in the terrestrial planets category) are bigger though. Why?

 

[El_Machinae]

This thought has a little problem - you're assuming constant distance between Sol and Tau Ceti.

That's true, I was. I wonder how much of a difference that makes? Where was Tau Ceti 65 million years ago?

 

[Winner]

That's true, I was. I wonder how much of a difference that makes? Where was Tau Ceti 65 million years ago?

I'd say very far away, it's velocity relative to Sol is 37 km/s. If I didn't make a mistake, that would put roughly 8000 light years away at the time of the Chixulub impact. Of course, it seems Tau Ceti is a pretty old star, maybe as much as 10 billion years old. It had been around before the nebula from which Sol came even formed.

Oh, and according to Sol Station, the purported planet is at the very inner edge of the habitable zone, thus it is very likely a Venusian hellhole. BUT if you look at the orbital animation here, you'll notice a conspicuous gap between the last two planet. It is very likely in my opinion that a smaller planet, one too small to be detected by the radial movement method, would fit there nicely. So all hope is not lost